What's in a Name?

What's in a Name?

The final topic I want to cover in this chapter is the names of the various pieces that make up Java's technology-specifically, the acronyms you constantly come across whenever you read or talk about Java, such as JVM, JRE, JDK, J2EE, and so on. Here they are, in no particular order of importance:

• JDK: The Java Development Kit-that is, the toolkit for developers that includes the Java compiler and the runtime environment. To write Java programs, you need the JDK. This term was used with the original versions of Java (1.0 and 1.1) and abandoned with version 1.2 in favor of SDK. But with versions 5.0 and 6, the term JDK is officially back in vogue.

• SDK: The Software Development Kit-what Sun called the JDK for versions 1.2, 1.3, and 1.4.

• JRE: The Java Runtime Environment-the program that emulates the JVM, so that users can run Java programs. To run Java programs, you need only download and install the JRE.

• JVM: The Java Virtual Machine-the platform-independent machine that is emulated by the JRE. All Java programs run in a JVM.

• Java SE: Java Standard Edition-a term that describes the Java language and the basic set of API libraries that are used to create Windows and applet applications. Most of this book focuses on Java SE.

• J2SE: Java 2 Standard Edition-an older term for the Java language and basic libraries (for Java versions 1.2 through 1.5).

• Java EE: Java Enterprise Edition, also known as J2EE (Java 2 Enterprise Edition)-an expanded set of API libraries that provide special functions, such as